fixed 27194934 from https://gitee.com/lilong32/docs/pulls/3468

Add bluetooth example code type as JS
Signed-off-by: Nlee <lilong32@huawei.com>

zh-cn/application-dev/reference/apis/js-apis-bluetooth.md

@@ -8,7 +8,7 @@
 
 ## 导入模块
 
-```
+```js
 import bluetooth from '@ohos.bluetooth';
 ```